My sister has waited for the last two years for her house to be completed. She is buying a new build and she was supposed to close two weeks ago and pick up the keys. However on the day she was supposed to close the seller phoned her to say he would not sign house over unless she would sign a letter to say that she would not sue for the rent that she has being paying. Originally on signing contracts he agreed to pay her rent if there was a delay on completion. Her solicitor has advised her not to sign as this is blackmail. Her solicitor has sent a letter to his solictor demanding that he sign. This was two weeks ago and she has heard nothing. Her solicitor says that she will ring her as soon as she has news. My sister is tempted to sign anything to get into the house. The backrent will amount to about 10,000. She has put a lot of money into the house.ie. tiles, kitchen,flooring etc. My sister is in bits. She was hoping to be in by Christmas. She is renting a 2 bed. apartment at the moment with 3 kids and are falling over boxes. What can she do? What is the worst that can happen. Can he refuse to sell her the house? Please advise.